Analytical Techniques

INAA

Instrumental neutron activation analysis is a chemically non-destructive technique of elemental analysis
used to determine mass fractions of as many as 40 elements in a variety of materials. Samples are packaged
as received, irradiated with neutrons. The elements comprising the sample undergo neutron capture resulting
in the formation of radioactive product nuclides. The gamma radiation is measured; the energy of the
radiation indicates from which element the product nuclide was formed and the amount of radiation at a given
energy is directly proportional to the amount of that element. For more information click here -> INAA.

RNAA

Radiochemical neutron activation analysis (RNAA)is used when greater sensitivities are required than are
provided by INAA. By performing radiochemical separations on the irradiated material, the element or class
of elements of interest are isolated to enhance sensitivity by eliminating interferences and reducing background
count-rates. For some applications, detection limits can be improved by up to three orders of magnitude as
compared with INAA. For more information click here -> RNAA.

PGAA

Prompt gamma ray activation analysis (PGAA) is used for the analysis of light elements such as H, B, C, N,
as well as for the heavy elements Cd, Sm, Gd. PGAA is used to complement INAA by allowing determination of
elements that do not form radioactive products after irradiation (e.g., H and B), and elements for which
the half life is too long to be conveniently measured by INAA (e.g., C.). PGAA also provides a second method
for analysis of some elements that are determined routinely with INAA (e.g., Na, Cl, K, Sm, Gd). PGAA is a
neutron beam technique in which the gamma rays are measured during sample irradiation. In this way samples that
are too large or unsuitable for in-core irradiations may be analyzed. There are two PGAA facilities at the NIST
Center for Neutron Research, one using a cold neutron beam and the other using a thermal neutron beam. For more
information click here -> PGAA.

NDP

Neutron depth profiling is a non-destructive, neutron beam, analytical technique used to determine the concentration
of elements such as boron, lithium, and nitrogen, as a function of depth in near surface regions of a variety of
materials. For more information click here-> NDP.

Neutron Focusing

Neutron focusing is a technique used to concentrate and direct a neutron beam onto a small area. Focusing
has been combined with both of the analytical cold neutron beam techniques, CNPGAA and NDP, to enhance the
spatial resolution and sensitivities for analyses of small samples.
For more information click here-> Neutron focusing.